Java Class子类变量引用

Question

我一直在类里面遇到“找不到符号”错误。父类(super class)明明声明了变量，子类却看不到。除了子类 RecordViewer 中 JLabel 的新构造函数外，我没有收到任何错误。

 class RecordViewer extends JDialog{
     private JButton next;
     private JButton prev;
     private JLabel label;
     private int current;

     public RecordViewer(CDinventoryItem [] array){
         super();
         current = 0;
         final CDinventoryItem [] items = array;

         label = new JLabel(items[getCurrent()]);

从我的 CDinventoryItem 类预定义 toString...

        @Override public String toString(){

        //  Decimal foramting for the inventory values
        NumberFormat dformat = new DecimalFormat("#0.00");

        //  Formatting for the inventory output
        StringBuilder ouput  = new StringBuilder();
        String New_Line = System.getProperty("line.separator");

            ouput.append("The product number of my CD is: ").append(iPitemNumber).append (New_Line);
            ouput.append("The title of the CD is: ").append(sPtitle).append (New_Line);
            ouput.append("I have ").append(iPnumberofUnits).append(" units in stock.").append (New_Line);
            ouput.append("The total value of my inventory on this product is: ").append(dformat.format(stockValue())).append (New_Line);
            return ouput.toString();
        }

Answer 1

这是标准的 Java JLabel 吗？您正在尝试传递 CDinventoryItem 类型的对象，而 JLabel 将没有构造函数来处理这种参数，除非它正在扩展 String 或 Icon 类。